1. Field of the Invention
The present invention relates to a display device and its manufacturing process and uses. In particular, the invention relates to a display panel comprising a plurality of photo-sensors.
2. Descriptions of the Related Art
Due to the depletion of the ozonosphere over recent years, ultraviolet (UV) rays are less shielded, resulting in an increase in the UV irradiation intensity on Earth. In addition to causing many environmental problems such as abnormal weather, greenhouse effect, reduction of crop yields, and ecosystem imbalance, excessive UV radiation (especially UVA with a light spectrum ranging from 320 nm to 400 nm and UVB with a light spectrum ranging from 290 nm to 320 nm) also endangers people's health. For example, UV radiation can (1) cause black spots, freckles and furrows on the skin, (2) lead to premature aging of the skin due to damaged DNA, (3) increase the incidence of skin cancer, (4) decrease vitamin D levels in the body, (5) cause acute keratitis, conjunctivitis and chronic cataracts, and (6) weaken the immune system.
In addition to UV rays, sunlight also comprises infrared (IR) rays with an intense thermal effect that is absorbed by objects for conversion into heat. When human bodies are exposed to the irradiation of IR rays, the absorption of IR rays may cause increased skin temperature, dilation and congestion of capillary vessels, and accelerated moisture evaporation of the epidermis, and thus, harms the skin. Moreover, IR rays may also impair the retina and iris in human eyes and thus, affect eyesight negatively. Even more so, when people are simultaneously exposed to the irradiation of both IR rays and UV rays, the effect of the IR rays will supplement the damaging effect of UV rays.
As a result, people should be immediately aware of the irradiation intensity of the harmful light rays such as UV and IR rays in their living environment (especially under the direct exposure of sunlight). Particularly, in beauty care and medical treatments, knowing the intensity of harmful light rays in the environment is important in deciding when to take protection measures, such as rubbing sun block on the skin, wearing sun glasses, or using sun umbrellas.
To increase awareness of irradiation intensity, a number of sensors have been proposed to detect UV rays. For example, U.S. Pat. No. 6,271,528 discloses a reusable personal light monitor, which utilizes a photostimulable phosphor as a storage medium to absorb the radiation energy of the light with a wavelength of 350 nm or less in the incident light. By using an apparatus with a readout, the radiation energy absorbed by the storage medium is calculated and converted into relevant messages (e.g., UV dose, UV index, etc.), which are then displayed on a panel of the personal light monitor. However, the user must have this personal monitor with him or her at all times to know the radiation intensity of the harmful light rays in the environment. This can be an inconvenience for the user.
To overcome this shortcoming, U.S. Pat. No. 6,541,775 proposes a portable information device capable of displaying UV intensity. It employs silicon carbide or a compound having an element of group III to group V of the chemical elements periodic table as a UV sensor and integrates the UV sensors with a portable device (e.g., a mobile phone, a personal digital assistant (PDA), and etc.). With this device, the user can find the intensity of the UV rays in the current environment via the portable device. However, the UV sensor has a lot of complicated materials, as well as a complicated manufacturing method.
Accordingly, the present invention provides a display panel for measuring and real time reporting a message about the intensity of an invisible light spectrum (such as UV, IR rays, and so on) of environmental light that does not require the use of expensive materials and can produce photo-sensors simultaneously in a thin film transistor (TFT) manufacturing process.